This invention relates to a hand held wrench with the capability of applying substantial additional amounts of torque when required and more particularly to a light weight hand held wrench with provision to transmit an external drive and to multiply the effect of the external drive.
A variety of hand tools are available to mechanics, hobbyists, "do-it-yourselfers", and others, for repairing automobiles, appliances, machines, and myriad other mechanical and electro-mechanical devices which abound in our modern society.
One of the more common frustrations for an individual who wishes to take on a repair himself is to discover that he lacks the specific tool to accomplish a specific task. For example, a basic collection of hand tools might comprise a set of socket wrenches, open and closed end wrenches, screw drivers, pliers, and hammers. However, these tools could prove to be inadequate when the individual comes up against the removal of a nut which is stubborn and requires more torque than he is able to apply, or where the work to be performed does not allow tool rotation or the use of a socket wrench.
The person faced with a problem of this type could of course obtain, at substantial expense, an over-sized or even a powered tool to resolve the predicament. A variety of special tools are available to meet such special needs, for example, the necessity to apply high torques to a nut when such is required to remove or tighten the nut. In French Pat. No. 2,314,808, there is shown a wrench-like tool with provision for the jaw to be driven through a gearing arrangement by a power drive. In U.S. Pat. No. 2,712,255 there is taught a gear-operated machine wrench for rotating propeller blade nuts. U.S. Pat. No. 4,064,772 illustrates a pneumatic tubing wrench wherein the jaw can be reversed in its direction by operating a valve. U.S. Pat. No. 4,098,151 teaches a powered wrench for tightening the brake on a locomotive.
All of the patented devices hereinabove described are relatively heavy, complicated and expensive which cannot be readily adapted for use in hand tools.